Prior to the present invention, various valve arrangements have been employed in HVAC systems to control the distribution of air in the passenger compartment of a vehicle. In U.S. Pat. No. 4,683,931, assigned to the assignee of this invention and hereby incorporated by reference, a rotary air valve seal is provided to produce effective sealing and long wear by having a sealing surface whose radius of curvature is offset from that of the rotary axis of the valve so that predetermined pressure closure is established at the curved sealing surface to tightly seal the air discharge when the valve is closed. Because of this offset sealing force diminishes to zero when the valve is rotated to affect window opening and frictional drag of the rotary seal is substantially reduced or eliminated.
The present invention is of the general category of the rotary seal in the above referenced patent but further provides for a new and unobvious valve assembly and mechanisms for moving the seal into engagement with or away from the window opening for improved control over the air flow therethrough. These mechanisms operate in a forthright and expeditious manner to eliminate excessive seal wear by friction and further to provide a new and improved airtight seal of the flow windows providing improved control over the flow of air to the passenger compartment in the vehicle.
The valve system of this invention provides essentially a linear temperature gradient affording the operator with a wide range of adjustments for precise and discrete selection of temperatures within the passenger compartment. Accordingly, the vehicle driver or passenger enjoys a precisioned control of the temperature in the vehicle passenger compartment. Incremental movement of the control by the operator results in directly corresponding incremental movement of the valve, and with better matching of control movement with valve movement there is precisioned control over compartment temperature. This invention further advantageously utilizes the inherent elasticity of the seal material, such as foam rubber, to assist in lift of the valve element from the window when the valve is actuated to open one of the windows.
These and other features, object and advantages will be more apparent from the following Detailed Description and Drawings.